>The mistake from a scientific point of view is how to define legacy preferences and how to measure such impacts.
The paper looked to define legacy preferences using multiple datasets where the school measured the importance of alumni relations in admissions. The datasets had to agree for (e.g., both say that alumni relations are "very important" regarding admissions). The measure used in the studies that showed no evidence was the level of alumni donations. It's pretty easily quantifiable. Other studies cited show that when legacy admissions were abolished there was not a statistically significant change in alumni donations.
You're comparing apples to oranges. The question is whether consideration of legacy status in admissions is causally linked to greater alumni giving. What you're asking is whether wealthy parents are willing to pay bribes to get their dull children into particular institutions. The two aren't comparable, because rich parents don't need to be alumni to pay bribes.
I am personally aware of a very large donation to MIT with the express purpose of admitting the high schooler, and I am less acquainted with a similar situation at Harvard. I have personally seen another alumni development quid pro quo, not a monetary donation, at MIT. Honestly it seems like common sense that the two are related. The mistake from a scientific point of view is how to define legacy preferences and how to measure such impacts. It is certainly there, itβs an interesting question as to how to measure it.